The Ethics of Least Action

I get a nice example of what might be termed a moral problem almost every time I go out in my car. The lanes round where I live are narrow, sometimes just wide enough for a car to go down. And quite often, going down these lanes, I come across someone coming in the opposite direction. And both of us come to a halt. And both of us wonder: who’s going to reverse back to a wider stretch of road where the two cars can pass? It’s a wordless negotiation about a small ethical dilemma.

What’s the right solution to this problem? Maybe some people would say that whenever you encounter it, you should always immediately reverse back. But if everyone did that, both drivers would reverse, and the hold-up would be prolonged. Or maybe people would say that people in small cars should defer to people in big cars. Or that people in old cars should defer to people in new cars.

I think that the right answer is: the person who should reverse is whoever needs to do the least reversing. That way, the delay for both drivers is minimised. Both are busy people, after all. And neither wants to spend any longer on the road than they have to. The solution is that of the option of least action.

Most times when I encounter this dilemma, the right decision gets made almost instantly. One person immediately reverses back down the road. And when they’ve reversed out of the way, the other car drives past, and in passing its driver acknowledges with a wave or a thumbs up the deference of the other driver, and gets a nod in return. Sometimes, when it’s not clear who should reverse, there can be a longer delay when neither driver immediately reverses.

But it doesn’t always work out quite so happily. Occasionally you come across one of those little old ladies who can’t reverse. My mother was one of them. And these little old ladies always expect the other car to reverse, even if they have to reverse half a mile. So I always check the sex and age of the other driver. If they’re female and elderly, I put my car into reverse immediately. Don’t ask me what happens when two little old ladies who can’t reverse encounter each other on a narrow lane.

The strangest thing about this dilemma is that everybody seems to know the answer to it. And yet as far as I know it’s not something that learner drivers are taught. There’s nothing about it in the highway code. Or there wasn’t the last time I looked.

Nor is the problem confined to roads. It’s encountered every day in passing through doors, or walking down narrow passages, or even along street pavements. Who is going to stop and step backwards or aside? Walking along a crowded street, hundreds of such accommodations are continually being negotiated and acknowledged.

The little old lady problem is encountered here too, in a slightly different form. The problem this time is that little old ladies can’t walk very fast. And that means that when a fit young man encounters a little old lady in a narrow passage, it’s almost always quicker for all concerned if he gives way to her, rather than she to him. The one who can move fastest gives way. And since fit young men are the fastest people on their feet, and little old ladies are the slowest, fit young men defer to everybody, and little old ladies defer to nobody. And men defer to women, because men are usually a bit faster on their feet than women.

And this is probably how the ‘Ladies First’ social convention arose. It was what emerged naturally from a least action principle. Particularly in a time when women’s mobility was hampered by long skirts and high heel shoes. But as soon as it was codified into the rigid rule – ‘Ladies First’ -, the least action principle became obscured. In fact, there are plenty of occasions on which it’s quicker for all concerned if ladies don’t go first. And so adherence to a one-size-fits-all rule like this is almost certain to result in unnecessary delay and obstruction from time to time. Rules like this are inefficient. It’s why rules usually have exceptions.

But in the case of roads sometimes the law steps in these days. There’s a narrow bridge not far from where I live which has a sign on one side telling drivers to give way to oncoming traffic, and another one on the other side telling drivers that they have priority over oncoming traffic. No negotiation is possible. The law has stepped in to tell drivers what they must do on this particular bridge. For the life of me I can’t see why this bridge has been singled out to have two large signs at each end, telling drivers who has to defer to whom. Maybe one day two little old ladies who couldn’t reverse met in the middle of it, and had to be rescued by the fire brigade.

And more and more, rather than leave decisions to drivers themselves, the law steps in to tell them what to do, and steps in with a one-size-fits-all rule, which is almost certainly bound to inconvenience everybody at some point or other. And there are more and more of these road signs, which make make decisions for drivers, and usually worse decisions than they’d make left to their own devices. In this manner, everyone is inconvenienced slightly more than they needed to be. And this puts a slight brake on the smooth operation of society. Everyone’s journey takes a little longer.

The worst example of this sort of legal intervention is the smoking ban. This is another one-size-fits-all rule, and which permanently inconveniences and obstructs fully a quarter of all people – smokers. It’s like telling occasionally-obstructive little old ladies that they aren’t allowed to drive cars anymore, anywhere, ever. And that they should just stay at home. A little old lady ban would mean a slight improvement in life for drivers like me. But it would be an enormous inconvenience for little old ladies. A total smoking ban offers a small benefit to people who are slightly inconvenienced by tobacco smoke, and an enormous inconvenience for smokers.

Furthermore, as more and more laws are introduced to govern more and more behaviour, people cease to govern themselves. Why should they govern themselves if somebody’s already doing the governing for them? And so the more rules and regulations that are introduced, the more personally irresponsible people are bound to become. Why should I make personal decisions about what is the best speed to drive at if some big sign tells me “30 mph”? Why should I make any personal decisions about where to smoke if there’s a big sign saying “No Smoking”? The personal decision-making has been overridden. So the more laws there are, the more irresponsible and inconsiderate everybody must become, because the law is taking the responsibility for considering other people away from them.

But the more irresponsible and inconsiderate everybody becomes, the more laws are demanded. And these laws result in even more irresponsibility and lack of consideration. So everything actually gets even worse.

But also, because the laws are always at very best only approximations for optimum (in terms of least action) behaviour, laws always obstruct people to some extent. The law that says that people must drive on the left hand side of the road is a law which makes everybody’s drive anywhere a little bit longer than it would have been if they’d had the use of the whole road. On the other hand, it’s also a law which minimises obstruction and delay through encounters with other vehicles. And on balance, it’s probably a law which expedites journeys more than it delays or slows them. Good laws are laws which, on balance, make everybody’s life easier for them. Good laws speed things up. Bad laws are laws which make everybody’s life harder for them. Bad laws slow things down.

People claim that seat belt laws save lives. This is disputed. But let’s suppose that it’s true that seat belts save 10 lives a year, and that a ‘life’ is the remaining time that anyone can expect to live, and that it’s about 30 years on average (more for young people, less for old people). Now let’s suppose that there are 20 million motorists in the country who put on and take off their car seat belts twice a day, and that it takes 5 seconds for them to perform each action. That’s 20 seconds per day for 20 million motorists, or 400 million seconds per day. Over a year, that’s 146 thousand million seconds. With about 31 million seconds in a year, that’s 4636 years. But the seat belts only saved 10 lives of 30 years remaining duration, or 300 years. So you gain 300 years, but lose 4636 years. So seat belts are a net drain on everybody’s precious time. This is just a guess of course. But what’s true of seat belts is probably true of almost all other health and safety regulations. And the more of these regulations there are, the more everyday life is slowed and hampered and delayed. And the worse life gets.

It always looks like more laws and more government will make people behave well and societies to flourish. The knee-jerk reaction to any new problem is to make a new law. But, for the most part, exactly the opposite is the truth. There should be less laws, not more laws.